from typing import List
class Solution:
  def merge(self, nums1: List[int], m: int, nums2: List[int], n: int) -> None:
    """
    Do not return anything, modify nums1 in-place instead.
    """
    while m > 0 and n > 0:
      if nums1[m - 1] < nums2[n - 1]:
        nums1[m - 1 + n] = nums2[n - 1]
        n = n - 1
      else:
        nums1[m - 1 + n], nums1[m - 1] = nums1[m - 1], nums1[m - 1 + n]
        m = m - 1
      if m == 0 and n > 0:
        nums1[:n] = nums2[:n]